1. Field of the Invention
This invention relates to rocket-engine nozzle extensions and especially to wall structures for increasing the strength and thermal-radiation capability of rocket-engine nozzle extensions.
2. Description of the Prior Art
Many rocket engines are made with nozzle extensions, so that the engine length may be decreased for storage by retracting the nozzle extension and may be increased to its full length by extending the nozzle extension section. The nozzle extension provides the engine with greater thrust.
Nozzle extensions are generally formed from sheet metal, such as Ti, stainless steel, columbium, etc.. The thin sheet metal is subject to vibration problems which can shatter the nozzle extension. Various expedients, such as circumferential thickening ribs known as hatbands, have been employed to increase structural stiffness, but other problems arise. The thermal conductivity of the ribs is different from that of the intermediate sheet metal areas and they expand at different rates, resulting in a warping of the shape of the nozzle extension.